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<title>Using Assembly Language with C (Using the GNU Compiler Collection (GCC))</title>

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<h3 class="section" id="How-to-Use-Inline-Assembly-Language-in-C-Code"><span>6.47 How to Use Inline Assembly Language in C Code<a class="copiable-link" href="#How-to-Use-Inline-Assembly-Language-in-C-Code"> &para;</a></span></h3>
<a class="index-entry-id" id="index-asm-keyword"></a>
<a class="index-entry-id" id="index-assembly-language-in-C"></a>
<a class="index-entry-id" id="index-inline-assembly-language"></a>
<a class="index-entry-id" id="index-mixing-assembly-language-and-C"></a>

<p>The <code class="code">asm</code> keyword allows you to embed assembler instructions
within C code.  GCC provides two forms of inline <code class="code">asm</code>
statements.  A <em class="dfn">basic <code class="code">asm</code></em> statement is one with no
operands (see <a class="pxref" href="Basic-Asm.html">Basic Asm &mdash; Assembler Instructions Without Operands</a>), while an <em class="dfn">extended <code class="code">asm</code></em>
statement (see <a class="pxref" href="Extended-Asm.html">Extended Asm - Assembler Instructions with C Expression Operands</a>) includes one or more operands.  
The extended form is preferred for mixing C and assembly language
within a function, but to include assembly language at
top level you must use basic <code class="code">asm</code>.
</p>
<p>You can also use the <code class="code">asm</code> keyword to override the assembler name
for a C symbol, or to place a C variable in a specific register.
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<li><a href="Basic-Asm.html" accesskey="1">Basic Asm &mdash; Assembler Instructions Without Operands</a></li>
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<li><a href="Constraints.html" accesskey="3">Constraints for <code class="code">asm</code> Operands</a></li>
<li><a href="Asm-Labels.html" accesskey="4">Controlling Names Used in Assembler Code</a></li>
<li><a href="Explicit-Register-Variables.html" accesskey="5">Variables in Specified Registers</a></li>
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